Apparatus for cooling and dehydrating hot pulpy solids



May 19, 1 953 n. B. VINCENT APPARATUS FOR COOLING AND DEHYDRATING HOT PULPY SOLIDS Original Fil'ed Nov. 27, 1945 Patented May 19, 1953 APPARATUS FOR COOLING AND DEHY- DRATING HOT PULPY SOLIDS Daniel B. Vincent, Tampa, Fla., assignor to Dan B. Vincent, Inc., Tampa, Fla., a corporation of Florida Original application November 27, 1945, Serial N 0. 631,072. Divided and this application March 29, 1949, Serial No. 84,184

4 Claims.

This invention relates to apparatus for cooling and dehydrating hot pulpy solids such as partially dehydrated citrus waste and the like, and aims generally to improve existing apparatus for the purpose.

Citrus cannery waste, 1. e. the peel, rag and seed from citrus canneries, is a desirable material for the-manufacture of stock and dairy cattle feed. The citru waste normally contains about 80 to 85 percent or more water and it must be comminuted and substantially dewatered for use. It is customary to dehydrate the comminuted waste by drying to a moisture content of not more than 10 percent to prevent decomposition of the feed. The drying and dehydrating step is usually effected in steam heated or other indirect heat driers and is the most costly step in the manufacture of citrus pulp feed.

Furthermore, the several treatment steps in processes for the manufacture of citrus pulp feed are advantageously arranged in continuous sequence so that the material moves continuously from its untreated state to its final dehydrated state ready to be sacked into sacks or bags- Prior to my invention, the drying or dehydrating step was the final processing step and the finished material emerging from the driers was of approximately 140 F. and too hot to be immediately bagged and sacked. When allowed to cool before sacking, additional handling expense was often involved.

The present application is a division of my prior copending application Serial No. 631,072, new Patent 2,471,363, filed November 27, 1945, disclosing and claiming an improved method and apparatus of producing a desirable feed from citrus cannery waste involving a number of correlated steps comprising (1) a preliminary treatment of the cannery waste with lime or other alkaline compound; (2) comminuting the waste (3) mixing and reacting the comminuted waste and lime; (4) mechanically pressing the waste to partially remove water; (5) drying the pressed solids in a current of hot products of combustion; and (6) cooling and further dehydrating the hot solids.

The present invention relates to an improved apparatus for cooling and finally dehydrating the hot pulpy solids. The hot solids leaving the primary dehydrating driers of the above described further dehydrated to a moisture content of about 10 percent preparatoryto' packaging for ship;

according to the present invention is designed to perform the latter step in an efficient and lexpeditious manner and to constitute the final treatment step in the continuous processing of citrus cannery waste to produce a citrus feed product ready for packaging or bagging.

A primary object of the invention, therefore,

is the provision of an improved apparatus for cooling and dehydrating citrus waste and the like.

Another object of the invention is the provision of an improved apparatus for cooling and gentle slipping and sliding movement in spreadout sheets intermittently interrupted by a gentle tumbling or turning action in the presence of a current of air at subatmospheric pressure. 4

These and other objects and advantages of the invention will be apparent to persons skilled in the art from a consideration of the attached drawings and annexed specification illustrating and describing preferredembodiments of the invention. i

In the drawings- Fig. 1 is a side elevational view partly in section of one form of cooling and dehydrating drum embodying the invention and suitable for practicing the method hereinafter described and claimed;

Fig. 2 is an enlarged fragmental sectional of the inlet end of the drum;

Fig. 3 is an enlarged fragmental sectional view of an intermediate section of the drum;

Fig. 4 is. an enlarged transverse sectional view of the drum as taken on the line 4-4 of Fig. 1, and illustrating the cascading movement of the material from a shelf on the ascending sidethere-. of; and l i Fig. 5 is a view similar to Fig. 4 illustrating the cascading movement of the material from a shelf on the descending side of the drum.

In general, the invention comprises moving the hot moist pulpy solids in a confined annular path;

ment. The cooling and dehydrating apparatu 1 View I) as between concentric shells of a rotary drum, the solids being spread out in sheet form on supporting shelves for a major portion of the time, the material being successively and repeatedly transferred from one supporting surface to another by .a gentle cascading action involvin only a very short fall so that a minimum of fines may be carried ofi in the current of air. In cascading the material from one supporting surface to another the fall is substantially less than the length of a chord of the drum passed through a free edge of a supporting shelfland preferably the cascading drop is less than half the length of such a chord. In this way the solids are only very briefly in suspension which permits the use of a much larger volume of air with correspondingly increased evaporating effect, and hence a more rapid and eflicient cooling and dehydration.

According to a preferred embodiment of the invention, the hot, moist pulpy solids, for example the partially dehydrated citrus pulp delivered from the separating device :of a primary dehydrating drier (not show-r1) is delivered to a cooling and dehydrating drum it -by means .of a feed chute l 1., the drum .lil providing a confined path for supporting and traversing the material to be cooled and dehydrated in substantially spread-out "condition through a large volume counter-current of'cooling air.

The drum to preferably comprises an outer shell l2 and a concentric inne shell l3 suitably connected together for rotation in unison as a unitary 'structure and providing therebetween an annular :passage through which the material to be treated is "moved a' spiral or helical path. The inlet end of the drum 1:0 maybe provided with a trusts-conical casing 15 surrounding the feedichute 11 and having its-large end fitted to an inwardly extending flange :M on thei-n letend of the drum to permit relative rotation "therebetween. The casing 15 provides a suction chamber surrounding the inlet chute i l and is connected at its --:'smailer end to the intake part or-a'zmotor driven fa'n 'l-l having its dischargeeutlet 18 leading to a centrifugal separator P9 of suitable design.

I he cbnoentricdrurn shells Hand -13 are suitably connected spaced-apart relation by any suitable -niean's, as for "example by spokes (not shown) *so that they may be rotated in unison. Any-suitablemeans may be provided for rotating the-drmn t'll, and in the illustrated "embodiment the *outer shell '1 2 may 'be "provided with circumfer'ent'ial "bands or *tires 52%] supported 'on and driven by rotating rollers 21 as is well understood in the art. Generally, the drum "will 'be rotated atf-rom about '5 to R. P. M. an'd'pre'ferab'ly :aZ-t about '10 R. 'M. for best results.

"The concentric shells'fl and 13 are provided with material-supporting plates or shelves 22 and 23 respectively, arranged .in staggered relation Within "the annular "chamber between the shells and are designed, in 'conjunction'with the shell surfaces,--'to"su1oport themateri'a'l to be treated in spread-out condition for a man or 'portionof the time it isW-ithin thedrum. "The shelves '22 and 23 are advantageously sheet metal plates disposed radially of the shell surfaces "and "longitndinally thereof and are of substantial width,

preferably exceeding one-half the Width 'of "the amiular chamber between the concentric *shell surfa'ces. Preferably the shelves 23- 011 th'e'inner shell l3 'alre disposed intermediate the shelves '2 2 on theouterzshell 1?, as shown, and their "adjacent surfaces overlap. Obviously the numberof 4- shelves on the respective drums may be varied in accordance with the requirements of the material to be cooled and dehydrated, but for practical purposes a minimum of four shelves on each of the shells is desirable.

The plates or shelves #22 and 23 prefera'bly stop somewhat short of the inlet end of the drum to form an inlet section 24 for receiving the material from the feed chute II. To assist in moving the material from the inlet section 24 into engagement with the plates 22 and 23 one or more spirally arranged blades 25 are secured to the inner periphery of the outer shell I2 and are preferably positioned so that they form continuations of th outer plates 20. .These act to move the materi-al quickly through the inlet section 24 to be engaged and lifted by the plates 22 and 23.

As will be apparent from Fig. l, the drum I!) is inclined downwardly slightly from the inlet or feed end to the discharge end so that rotation thereof will progress the material through the annular passage therebetween at a speed designed to accomplish the :desired cooling :and dehydrating effects. Generally th angle of inclination of the drum with respect to thehorizontal will vary from about 3 to about fi'idegrees depending upon other factors including characteristics of the material being treated, :the siz'ezand construction-of the drum and the revolutions per minute. if "desired, the :spiral iblatie :25.:m'aybe continued alon the inner iisnriace of the nuter shell 12 throughout the length thereof to 'faxzilitate movement of the :material longitudinally through the drum.

In "operation the ho't pulpysolidsandflihe material entering the revolving drum through ithe fee'd chute Y I l falls into the inlet section a: where it slides downwardly under thezaction of gravity and the conveyingaction of the spiral blades 25 until 'it is engaged bynne of-the platesli. This plate acts a shelf to 'l'i fit the materialas the drum rotates, and as the shelf approachesayen tical position, the -material slides off-and is oasca'ded into the space between-two pla'tes 2 3 upon the convened surface of-the inner shell -1 3. With continued rotation the material may be carried over to the other side of-the drum where-it slides oil of a plate 23 and drops onto 'the conceived surface of the outer drum. When th -next plate 22 reaches the fallen *masst-h'e operation is repeated.

Due to the inclination of 'the"-drum and ofthe shelves 2? and ZB carried thereby the materialisl shifted along-the shelves and advanced along the drum 'as-compared to that which'itpccupied at the bottom of the drum. Likewise as thematerial cascades -from thelpl'ates 22 to the 'c'onvexed surface o f't'he inner shell"23 and from'thereto thebott'omp'f 'th'enute'r drum it strikes advanced portions of these surfaces and is .'further advanced along the drum toward the discharge end thereof. During this progressive movement of the material through 'the drum .a current .of air is "drawn th'erethroughf'by the blower J1 over the material asit lies spread out and as it cascades from one shelf to another. Ila-addition, ah-is drawn also along the supporting shelves .and through the inner shell I3 thereby .coolingthem so that -it exerts a cooling effect on any material resting thereon and on the air passing between the shells. Practically the entire momernent-lo'f the materialthrough the drum'is that of slipping and sliding alonginspread-out sheets which are separated and "re-formed at each "tumbling or cascading drop from one plate "to "an adjacent surface. This cascading or drop is of such short length, preferably less than half thelength of a chord of the drum [0 passed through a free edge ofthe shelves 22 or 23, that a large volume of cooling air may be employed without danger of carrying off an excessive amount of fines or similar particles. This enables the current of air at subatm-ospheric pressure to carry off any escaping moisture from the hot material to continue the drying operation by evaporation of water and to cool'the material quickly by the refrigerating effect of the evaporation.

'Normal atmospheric air can be used as the drying medium even on very humid days because the entering air encounters material of a warmer thanatmospheric temperature and it becomes progressively warmer as it" encounters still warmer material. The capacity of air for carrying moisture is approximately doubled with every 20 F. rise in temperature. Assuming anoutside temperature of 72 F., feed entering the cooling drum at 140 F. and the air entering at "72 F. and leaving at 132 it will be seen that the rise of 60 F. in the temperature of the air has almost doubled its water-carrying capacity three times, giVil'lg a final capacity of about six times the original capacity. Competent authorities state that one pound of air at 72 F. will carry 0.016691-pound of water while one pound of air at 132 F. will carry, 0.118548 pound of water. Hence, under the conditions stated, each pound of air circulated through the drums has the potentiality of picking up about 0.10157 pound of water.

As the cooled and dehydrated material passes from the open discharge end of the drum I0 it falls into a discharge chute 30 fro-m which it may be conveyed to a suitable sacking or packaging device, not shown. The material passed through the drum will have been cooled from approximately 140 F. to approximately 75 F. and will have been dehydrated from a moisture content of about 12 or 13 percent to about percent or less.

Thus the present invention provides an apparatus which is highly effective for its intended purpose of cooling and dehydrating hot waste material such as treated citrus waste. It has the advantage that solids passing between the drums are continuously subjected to a slipping, sliding and tumbling action so that the individual particles thereof are uniformly and completely exposed to the cooling and dehydrating effects of the current of subatmospheric air. It has the further advantage that atmospheric air may be used without prior conditioning, thus eliminating the need of costly and complicated apparatus for this purpose. Although designed primarily for cooling and dehydrating treated citrus waste, the apparatus of this invention is applicable to the treatment of other materials of a similar nature and such uses are contemplated aswithin the scope of the invention.

Various modifications of the invention described and illustrated will most likely occur to those skilled in the art to which the invention relates and may be made without departing from the spirit of the invention, the scope of which is indicated in the attached claims.

I claim:

1. An apparatus for cooling and dehydrating hot solids comprising a rotatably mounted drum member having inner and outer cylindrical shells, said inner shell having a substantial surface area concentric with the outer shell whereby there is defined an annular space therebetween, inlet means for feeding hot solids into one end of said drum member, outlet, means i for discharging cooler treated solids from the opposite end, of said drum member, a plurality of shelf plates secured totthe inner surface of said outer shell longitudinally thereof and extending inwardly toward said inner shell and terminating in inner edges spaced from said inner shell, a plurality of shelf plates secured to the outer surface of said inner shell longitudinally thereof and extending outwardly between said first named plate members in overlapping relation therewith and terminating in outer edges spaced from said outer shell, a spiral feed band extending inwardly from the inner surface of the outer shell into proximity with the outer edges of the shelf plates on the inner shell, the last saidshelf plates being attached, to the inner margin of the spiral feed band, said drum member being inclined downwardly from the inlet to the outlet ends whereby material introduced into said outer drum will be progressed therethrough with a cascading, sliding and slipping movement over the surfaces of the inner and outer shells and the shelf plates, and means for subjecting the materialto a current of air as it moves through said outer drum member to cool and dehydrate it.

2. An apparatus for cooling and dehydrating hot solids comprising a drum 1 member, inlet means for introducing hot solids into said drum member for passage therethrough, a spirally arranged band secured to the inner surface of said drum member .and extending throughout a substantial portion of its length, a plurality of longitudinally extending plates mounted in said drum member and having portions thereof positioned between the turns of said spiral band and secured to the inner surface of said drummember, an inner shell mounted in said drum and held in position therein by a plurality of longitudinally extending plate members, said plate members having their inner edges secured to said inner shell and their outer edges secured to the turns of said spiral band where they come into contact, means for rotating said drum member and said inner shell, and means for passing a current of air through said drum member in contact with the hot solids passing therethrough.

3. An apparatus for cooling and dehydrating hot solids comprising a drum member, means for introducing hot solids into said drum member for passage therethrough, a spirally arranged band secured to the inner surface of said drum member and extending throughout a substantial portion of its length, a plurality of longitudinally extending plates mounted in said drum member between the turns of said spiral band and extending radially inward therefrom, an inner shell mounted in said drum member concentrically thereof, plate members secured to said inner shell and extending outwardly intermediate said first mentioned plate members, the last said plate members being secured at their outer portions to the inner margin of the spiral band, means for rotating said drum member and said inner shell, and means for passing a current of air through said drum member in contact with hot solids passing therethrough.

4. Apparatus for continuously cooling moist hot pulpy solids of a moisture content of at least 12 percent and dehydrating them to a moisture content of not more than 10 percent comprising a rotary drum having concentric inner and outer shells presenting radially opposed concaved and l fibnvexecl surf-aces, inlet means ion ml/roaming lmt pulpy solids 6'0- athe spaee ibetywem said shells at one and of said drum, means im' \dl'schamgmg treated material 35mm the nppwsite end of said 01mm, meamsiiorzestahlishing a- :lange volume current of cooling air through said drum between said :shells in a, direction :cmmter "m the mauvemeat 61 sends merethrough, a plmality of "shelf plates aseeured 1:0 the inner surface of :said miter she'll longitudinally wthen'eof extending mwarfily therdzwm and terminating edges spaced mom said inner shell for lifting material from the mom tom at the Huber 40f szn'rl shells, :carrying it lupwamly spmad out imam thererm, and 213- cadin'g it dnwnwamdly unto the upper convex surface of :the inner *of .said shells, .a plurality of shelf mates secured $013116 mm surface M said inner shell longitudinally thereof extending outwardly therefmm and terminating in edges spaced from swidflouter she'll :fm" carrying material cascaded downward-13 1011 .said upper convex sur face upwardly and raver: to the :oppusite :side of the drum while spread o=ut thereon, and then cascading it dowmrdly to the concave surface 0f. said cuter shelLjthe @uter edges of tlhe shelf plateszm the innerwshell @ovarlappingthe inner-edges "0f the shelf plates on the outer shell, and a spiral feed band extending inwardly tram the inner "surface of the outer shell, the outer portions :of the shelf plates on che inner :shell being secured to the '8 mamgln 01' the-spiral band, 'wherebyithe inner shell is secured law the outer shell and ithe spiral band feeds the solids longitudinally of the drum when lihe soll'cls are an the inner periphery of the -outer shell.

DANIEL B.

'Befieren'ces Gitedi-n the file *of this paltm;

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